Mast top



G. F. WATTS.

MAST TOP.

APPucATloN HLED JuLY1.3,1921.

` Patented July 18, 1922.

il! T11 Uitl?? GEGRGE F. `llA'lWlS, OF BOSTON, MASSACHUSETTS.

. MAST TO?.

TLAZSQET?.

Application filed July 13,

To @ZZ @710m t may concern.'

Be it known that l, (5l-Ronan F. lVA'r'rs, a citizen ot the United States, residing at the city of Boston, county of Suffolk, State of Massachusetts, have invented new and useful Improvements in Mast Tops, of which the following is a specification.

This invention relates to an improvement in mast tops, and more particularly adapted for masts which have a pivotal connection with the foot block.

The invention consists of a base plate attached to the top of a mast and having a gudgeon pin; and mounted on the base plate is the spider plate, the base plate and spider plate having ball bearings interposed therebetween whereby'the base plate may freely rotate with respect to the spider plate. Located between the spider plate and gudgeon pin are roller bearings to prevent the spider plate from binding on the pin.

The spider plate has attached thereto guy wires, and in raising a load with a guy derrick the top of the mast is pulled in the direc-tion of the boom stressing the back guys, and with the usual slack in the guys the mast gets out of plumb. The tilting or inclining of the mast toward the boom causes the spider plate to bind on the gudgeon pin. making it very difficult to rotate the mast. This condition is very common in derricks of this character, and it has been de monstrated with the use of the present invention that this objection is overcome. The ball bearings between the base plate and spider plate will equalize the pressure which is exerted on the spider plate and the roller bearings around the gudgeon pin will obviate the binding of the spider plate on the gudgeon pin, thereby making it possible to freely rotate the mast.

The invention consists of certain novel features of construction and combinations of parts which will be hereinafter described and pointed out in the claims.

In the accompanying drawing:

Figure 1 is a view in elevation showing the invention applied to the top cfa derrick mast;

Figure 2 is a vertical section view of the invention; and i Figure 3 is a top plan view of the portion of the spider plate and gudgeon pin broken away to more clearly illustrate the location 5 of the anti-friction bearings.

.ln the drawings, A represents the metallic Speccatan of Letters Patent.

Patented July 18, 1922.

192i. Serial No. 484,459.

skeleton mast having referably four angle iron plates l, l, locate on each of the sides thereof. Mounted upon the mast is a base plate 2 which is provided with a downwardly extending hub 3 projecting` into the mast A a sufficient distance to form a proper bearing for the base plate. A. plurality of holes t are formed in the base plate through which bolts 5 extend. The heads of the bolts are received in countersunk portions formed in the base plate so that the heads are below the surface of the base plate. These bolts 5 extend through the angle iron plates 1 and nuts 6 are screwed upon the ends of the bolts for securely attaching the base plate to the mast. A gudgeon pin 7 is received in the hub 3 of the base plate and is held therein by a transverse pin 8. Mounted upon the base plate 2 and the gudgeon pin 7 is a spider plate 9. The spider plate 9 is provided with an angular flange 10 on its lower surface which encircles or surrounds the upper portion of thebase plate 2. lnterposed between the spider plate 9 and the base plate 2 are a plurality of ball bearings l1 which form an anti-friction bearing between the two plates and allow the mast and base plate to rotate freely with respect to the spider plate 9. Suitable race ways l2 and 13 are formed in the spider plate 9 and base plate 2, respectively, for the reception of the balls 11.

Located between the gudgeon pin 7 and the hub 14 of the spider plate 9 are roller bearings 15. The rollers 15 are ournaled in a cage 16 and are suitably spaced apart for forming a proper anti-friction bearing between the pin 7 and plate 9. A weather cap 17 is mounted on the gudgeon pin 7 and over the hub 14 for maintaining the spider plate upon the base plate 2 and preventing the ingress of dirt or moisture to the bearings. The cap 17 is secured to the pin 7 by a transverse pin 18. A lubricating opening 19 is formed in the spider plate 9 so that a suitable lubricant may be introduced between the plates 2 and 9 for lubricating the bearings and preventing any possibility of friction between the parts. Suitable ribs 21 having holes 22 therein are integrally formed with the spider plate 9 to which the usual guy wires are attached for supporting the mast.

This invention is intended for use in connection with masts which are capable of rotation and which masts are either pivote@ or rotatably connected with a foot block. It has been one of the great objections with most masts which are capable ot rotation to provide' a suitable mast top which would permit the mast to rotate without binding or the creating ot friction between the mast and the mast top and thereby interfering` with 'the easy turning or rotating oit the mast. Wlhen a load is being handled by the boom, the mast will be caused to shift from the Vertical to an inclined position and gein erally toward the boom thereby placing' a strain on the guy wires, which are generally somewhat slack, thereby causing the spider plate 9 to assume a somewhat inclined posi` tion and creating` friction between the base plate 2 and the spider plate 9 as well as with the gudgeon pin 'i'. This friction which is created in this manner makes it rei-y ditlicnlt to rotate the mast without employing; a great many men or the use of a block and tackle to rotate the mast.` With this construction wherein the roller bearings are provided between the lcfudgeon pin and spider plate this lateral` thrust or stress which is exerted upon the spider plate will be overcomej and the rollers 15` together with the balls ll, which latter equalize `the pressure exerted upon the spider plate 9, will eliminate all friction between the base plate,` gudg'eon pin and spider plate.

Having` fully described my .invention7 what I claim as new and desire to secure by Letters Patent. is:

l. In a mast top. the combination with a derrick mast, a base plate mounted thereon and provided with a gndgeon pin, a spider plate mounted upon the base plate and surrounding` the gudgeon pin, and anti-friction means interposed between the spider plate and gudgeoii pin and between the spider plate and base plate.

2. In a derrick, the combination with a hollow mast, a base plate having a hub ein tending into the mast, means for connecting the base plate to the mast, a gudgeon pin on thebase plate, a spider plate mounted upon the base plate and surrounding the ggudgeon pin, and anti-friction means interposed between the spider platewand the gndgeon pin and between the spider plate and baseplate. j

Ina` derrick7 the combination with a mast and a base plate mounted thereon, a gudgeon pin connected to the base plate, a spider mounted upon the base plate and encircling` the gudgeon pin, roller bearings interposed between the spider plate and gudgeon pin, anti-'friction bearings located between thespider plate and base plate, and a cap carried by the gudgeon pin tor maintainingl the spider plate on the base plate and for protecting the bearings.

14C. In a derrick7 the combination of a hollow mast having;` angle plates thereon, a base pla-te mounted upon the mast and having a hub extendinginto the mast, means for connecting` the base plate to the angle plates7 a gudgeon pin carried by thebase plate, a spider plate mounted on the base plate, and anti-friction means interposed between the grudgreon pin and spider plate and between the base plate and spider allaite.

` GEORG l F. VATTS. 

